Table_2_Modifying Anthocyanins Biosynthesis in Tomato Hairy Roots: A Test Bed for Plant Resistance to Ionizing Radiation and Antioxidant Properties in Space.XLSX

Gene expression manipulation of specific metabolic pathways can be used to obtain bioaccumulation of valuable molecules and desired quality traits in plants. A single-gene approach to impact different traits would be greatly desirable in agrospace applications, where several aspects of plant physiology can be affected, influencing growth. In this work, MicroTom hairy root cultures expressing a MYB-like transcription factor that regulates the biosynthesis of anthocyanins in Petunia hybrida (PhAN4), were considered as a testbed for bio-fortified tomato whole plants aimed at agrospace applications. Ectopic expression of PhAN4 promoted biosynthesis of anthocyanins, allowing to profile 5 major derivatives of delphinidin and petunidin together with pelargonidin and malvidin-based anthocyanins, unusual in tomato. Consistent with PhAN4 features, transcriptomic profiling indicated upregulation of genes correlated to anthocyanin biosynthesis. Interestingly, a transcriptome reprogramming oriented to positive regulation of cell response to biotic, abiotic, and redox stimuli was evidenced. PhAN4 hairy root cultures showed the significant capability to counteract reactive oxygen species (ROS) accumulation and protein misfolding upon high-dose gamma irradiation, which is among the most potent pro-oxidant stress that can be encountered in space. These results may have significance in the engineering of whole tomato plants that can benefit space agriculture.

对特定代谢途径的基因表达操控，可用于在植物中实现高价值分子的生物富集以及目标品质性状的获得。在太空农业（agrospace）应用中，若能通过单基因策略调控多种植物性状，将极具实用价值——因为太空环境会影响植物生理的多个方面，进而干扰其生长发育。本研究以表达MYB类转录因子（MYB-like transcription factor）PhAN4的MicroTom（微型番茄）毛状根培养物为测试体系，该转录因子源自矮牵牛（*Petunia hybrida*），可调控花青素的生物合成，旨在为适配太空农业应用的生物强化型完整番茄植株提供研究平台。PhAN4的异位表达（ectopic expression）促进了花青素的生物合成，可鉴定出5种主要的飞燕草素、矮牵牛素衍生物，以及番茄中罕见的天竺葵素基与锦葵素基花青素。与PhAN4的功能特性相符，转录组分析（transcriptomic profiling）显示，与花青素生物合成相关的基因均出现上调表达。值得注意的是，研究还观测到转录组重编程（transcriptome reprogramming）现象，该重编程可正向调控细胞对生物胁迫、非生物胁迫以及氧化应激的应答反应。PhAN4阳性毛状根培养物展现出显著的抗氧化能力：在高剂量γ射线辐照（gamma irradiation）处理后，可有效清除活性氧（reactive oxygen species, ROS）积累并缓解蛋白质错误折叠；而γ射线辐照是太空环境中可遭遇的最强促氧化胁迫（pro-oxidant stress）之一。上述研究结果可为适配太空农业的工程化完整番茄植株培育提供重要理论支撑。